A chip resistor mounted on small electronic equipment etc. has pad electrodes facing each other on an insulating substrate and a resistive element bridging between those pad electrodes. In such a resistor, when the resistive element is connected to an exterior electrode via a pad electrode, the area of the pad electrode is added to the area of the resistive element in a laminated body. Therefore, for example, a circuit board having a structure in which a resistive element is formed directly above a via-hole without preparing such an electrode, directly connecting it to the electric conductor in the via-hole has been proposed in Japanese Patent Application Laid-Open No. 6-77660.
Since in a conventional chip resistor including a resistive element (resistive layer), a resistance film exposed from the edge face of a laminated insulator has a small area, there is a problem with stability of adhesion of the edge face of the resistance film to an exterior electrode and lack of reliability of the same. In view of this problem, technology of increasing the exposure area of a resistance film is disclosed in Japanese Patent Application Laid-Open No. 7-201539.
In the case of the ceramic circuit board disclosed in Japanese Patent Application Laid-Open No. 6-77660 as described above, electrodes are made unnecessary so as to allow implementation of a highly dense circuit on a circuit board or miniaturization of the circuit board. However, separately, a terminal for resistance measurement and corresponding inner layer pattern are additionally required. There is thus such a problem that high density integration is limited. Moreover, since such a conventional ceramic circuit board needs correction of resistance by laser trimming, a substrate structure in which a resistive element is formed on the top surface of the substrate is employed. There is a problem that such a structure is inapplicable to a ceramic circuit board having a multilayer resistor structure in which resistive elements are arranged between layers.
On the other hand, according to the chip resistor disclosed in Japanese Patent Application Laid-Open No. 7-201539, connection state between a resistive element and exterior electrodes, that is, connectivity between a resistance film and an electric conductor section depends upon the cross sectional area of a resistance film, which appears on the edge face of an insulator. Moreover, there is a limit in increase of the area of the resistance film because of its properties. As a result, manufacturing of a chip resistor that secures perfect connectivity with an exterior electrode requires advanced manufacturing technology.
The present invention is provided in light of the problems mentioned above, and aims to provide a laminated ceramic body, which allows space saving and controls variation in internal layer resistances, and a manufacturing method thereof.